Eisenhuettenstadt, just over an hour east of Berlin, was once the East German socialist model New Town with, at its peak, over 50,000 inhabitants. Today there are only just under 30,000 left. Eisenhuettenstadt (which translated means literally Ironworks City) was built around....well, have a guess......yes, an ironworks.
It was built in the 1950s after the East German 16 Rules of City Planning (Die 16 Grundsaetze des Staedtebaus) which is based on the harmonic combination of work, home, culture and recreation. Today it is unfortunatley only a shadow of it's former self with an increasingly ageing population (The average age of Eisenhuettenstadt in its 1950s heyday was early 20s. Now it is approaching 50 and more than a third of the population is over 60).
Still, it's well worth a visit if socialist architecture is your thing. It has also some of the best socialists mosaics I have ever seen, my favourite is inside the town hall.